PaulS:
But, it won't work with those pins. Only pins 0 and 1 can be used on the 85 (as far as I know, anyway).
Not so.
Here are two examples using pins 3 and 4:-
ATtiny85 & ATtiny84 Analog Pins, Serial Communication, etc.
Serial Communication on a ATtiny85 with the SoftwareSerial Library.
And in this article, half-way down the page:- Is SoftwareSerial left out for the ATTiny85/84?